Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C7/00—Separating solids from solids by electrostatic effect
  • B03C7/003—Pretreatment of the solids prior to electrostatic separation
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/03—Powdery paints
  • C09D5/033—Powdery paints characterised by the additives
  • C09D5/034—Charge control agents
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/097—Plasticisers; Charge controlling agents
  • G03G9/09733—Organic compounds
  • G03G9/09741—Organic compounds cationic
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/097—Plasticisers; Charge controlling agents
  • G03G9/09733—Organic compounds
  • G03G9/0975—Organic compounds anionic
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/097—Plasticisers; Charge controlling agents
  • G03G9/09783—Organo-metallic compounds
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G7/00—Capacitors in which the capacitance is varied by non-mechanical means; Processes of their manufacture
  • H01G7/02—Electrets, i.e. having a permanently-polarised dielectric
  • H01G7/021—Electrets, i.e. having a permanently-polarised dielectric having an organic dielectric
  • H01G7/023—Electrets, i.e. having a permanently-polarised dielectric having an organic dielectric of macromolecular compounds

Definitions

• the present invention lies within the technical field of charge control agents in toners and developers for electrophotographic recording processes, in powders and powder coating materials for surface coating, and in electret materials, especially in electret fibers, and in separation processes.
• a latent charge image is produced on a photoconductor.
• This latent charge image is developed by applying an electrostatically charged toner which is then transferred to, for example, paper, textiles, foils or plastic and is fixed by means, for example, of pressure, radiation, heat or the action of solvent.
• Typical toners are one- or two-component powder toners (also known as one- or two-component developers); also used are speciality toners, such as magnetic toners, liquid toners or polymerization toners, for example.
• polymerization toners are meant those toners which are formed by, for example, suspension polymerization (condensation) or emulsion polymerization and lead to improved particle properties in the toner. Also meant are those toners produced basically in nonaqueous dispersions.
• One measure of the quality of a toner is its specific charge q/m (charge per unit mass).
• q/m charge per unit mass
• the principal, decisive quality criteria are the rapid attainment of the desired charge level and the constancy of this charge over an extended activation period.
• the insensitivity of the toner to climatic effects such as temperature and atmospheric humidity is a further important criterion for its suitability.
• Both positively and negatively chargeable toners are used in copiers and laser printers, depending on the type of process and type of apparatus.
• charge control agents To obtain electrophotographic toners or developers having either a positive or negative charge, it is common to add charge control agents. Since the charge of toner binders is in general heavily dependent on the activation period, the function of a charge control agent is, on the one hand, to set the sign and level of the toner charge and, on the other hand, to counteract the charge drift of the toner binder and to provide for constancy of the toner charge.
• Charge control agents which are not able to prevent the toner or developer from showing a high charge drift (ageing) during a prolonged period of use, and which even cause the toner or developer to undergo charge inversion, are hence unsuitable for practical use.
• the charge control agents should have sufficient thermal stability and good dispersibility.
• Typical temperatures at which charge control agents are incorporated into the toner resins, when using kneading apparatus or extruders, are between 100° C. and 200° C. Accordingly, thermal stability at 200° C. is of great advantage. It is also important for the thermal stability to be ensured over a relatively long period (about 30 minutes) and in a variety of binder systems. This is significant because matrix effects occur again and again and lead to the premature decomposition of the charge control agent in the toner resin, causing the toner resin to turn dark yellow or dark brown and the charge control effect to be wholly or partly lost.
• Typical toner binders are addition polymerization, polyaddition and polycondensation resins, such as styrene, styrene-acrylate, styrene-butadiene, acrylate, polyester and phenol-epoxy resins, and also cycloolefin copolymers, individually or in combination, which may also include further components, examples being colorants, such as dyes, pigments, waxes or flow assistants, or may have these components added subsequently, such as highly disperse silicas.
• resins such as styrene, styrene-acrylate, styrene-butadiene, acrylate, polyester and phenol-epoxy resins, and also cycloolefin copolymers, individually or in combination, which may also include further components, examples being colorants, such as dyes, pigments, waxes or flow assistants, or may have these components added subsequently, such as highly disperse silicas.
• charge control agents may also be used to improve the electrostatic charge of powders and coating materials, especially in triboelectrically or electrokinetically sprayed powder coating materials as are used to coat surfaces of articles made from, for example, metal, wood, plastic, glass, ceramic, concrete, textile material, paper or rubber.
• Powder coating technology is used, for example, when coating articles such as garden furniture, camping equipment, domestic appliances, vehicle parts, refrigerators and shelving and for coating workpieces of complex shape.
• the powder coating material, or the powder receives its electrostatic charge, in general, by one of the two following methods:
• the powder coating material or powder is guided past a charged corona and is charged in the process; in the case of the triboelectric or electrokinetic method, the principle of frictional electricity is utilized.
• the powder coating material or powder in the spray apparatus receives an electrostatic charge which is opposite to the charge of its friction partner, generally a hose or spray pipe made, for example, from polytetrafluoroethylene.
• Typical powder coating resins employed are epoxy resins, carboxyl- and hydroxyl-containing polyester resins, polyurethane resins and acrylic resins, together with the customary hardeners. Resin combinations are also used. For example, epoxy resins are frequently employed in combination with carboxyl- and hydroxyl-containing polyester resins.
• mixed powders powder coating materials whose resin base consists of a combination of epoxy resin and carboxyl-containing polyester resin.
• the mixed powders form the basis for the powder coating materials used most commonly in practice.
• Inadequate charging of the abovementioned powders and powder coating materials results in an inadequate deposition rate and inadequate throwing power on the workpiece to be coated.
• the term “throwing power” is a measure of the extent to which a powder or powder coating material is deposited on the workpiece to be coated, including its rear faces, cavities, fissures and, in particular, its inner edges and corners.
• charge control agents are able to improve considerably the charging and the charge stability properties of the electret materials, especially electret fibers (DE-A43 21 289).
• Electret fibers have hitherto been described mainly in connection with the problem of filtering very fine dusts.
• the filter materials described differ both in respect of the materials of which the fibers consist and with regard to the manner in which the electrostatic charge is applied to the fibers.
• Typical electret materials are based on polyolefins, halogenated polyolefins, polyacrylates, polyacrylonitriles, polystyrenes or fluoropolymers, for example polyethylene, polypropylene, polytetrafluoroethylene and perfluorinated ethylene and propylene, or on polyesters, polycarbonates, polyamides, polyimides, polyether ketones, on polyarylene sulfides, especially polyphenylene sulfides, on polyacetals, cellulose esters, polyalkylene terephthalates, and mixtures thereof.
• Electret materials, especially electret fibers can be used, for example, to filter (very fine) dusts.
• the electret materials can receive their charge in a variety of ways, for instance by corona or triboelectric charging.
• charge control agents can be used in electrostatic separation processes, especially in processes for the separation of polymers.
• the externally applied charge control agent trimethylphenylammonium tetraphenyl borate J. Electrostatics 30, (1993) 203-212
• Y. Higashiyama et al. J. Electrostatics 30, (1993) 203-212
• charge control agents the triboelectric charging characteristics of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) are extremely similar.
• LDPE low-density polyethylene
• HDPE high-density polyethylene
• the charge control agents In addition to the external application of the charge control agents it is also possible to conceive in principle of their incorporation into the polymer in order, for example, to shift the position of the polymer within the triboelectric voltage series and to obtain a corresponding separation effect. In this way it is possible to separate other polymers as well, such as polypropylene (PP) and/or polyethylene terephthalate (PET) and/or polyvinyl chloride (PVC), from one another.
• PP polypropylene
• PET polyethylene terephthalate
• PVC polyvinyl chloride
• Salt minerals for example, can likewise be separated with particularly good selectivity if they are surface-treated beforehand (surface conditioning) with an additive which improves the substrate-specific electrostatic charging (A. Singewald, L. Ernst, Zeitschrift fur Physikal. Chem. Neue Folge, Vol. 124 (1981) 223-248).
• Charge control agents are employed, furthermore, as “electroconductivity providing agents” (ECPAs) in inks for inkjet printers (JP 05 163 449-A).
• Charge control agents are known from numerous literature references. However, the charge control agents known to date have a number of disadvantages, which severely limit their use in practice or even, in some cases, render it impossible; examples of such disadvantages are inadequate thermal stability, inherent odor, poor dispersibility or low stability in the toner binder (decomposition, migration). A particular weakness of many common commercial charge control agents is the inadequacy of their activity with respect to the desired sign of the charge (positive or negative charge), charge level or charge constancy.
• charge control agents should be ecotoxicologically unobjectionable.
• the object of the present invention was therefore to find particularly effective and ecotoxicologically compatible charge control agents.
• the intention is that the compounds should not only permit the rapid attainment and constancy of the charge but should also be of high thermal stability. Furthermore, these compounds should be readily dispersible, without decomposition, in various toner binders employed in practice, such as polyesters, polystyrene-acrylates or polystyrene-butadienes/epoxy resins and also cycloolefin copolymers. Furthermore, their action should be largely independent of the resin/carrier combination, in order to open up broader applicability. They should likewise be readily dispersible, without decomposition, in common powder coating binders and electret materials, such as polyester (PES), epoxy, PES-epoxy hybrid, polyurethane, acrylic systems and polypropylenes.
• PET polyester
• PES-epoxy hybrid polyurethane
• acrylic systems and polypropylenes polypropylenes.
• the charge control agents should be active even at very low concentration (1% or less) and should not lose this efficiency when in conjunction with carbon black or other colorants. Indeed, it is known of colorants that they can affect—in some cases lastingly—the triboelectric charging of toners.
• a negatively charged toner consisting of toner resin, colorant and a metallic additive for charge enhancement, obtainable from the reaction of a metal ion with one molar equivalent of an ortho-hydroxyphenol and two molar equivalents of an aromatic carboxylic acid in aqueous solution in the presence of a base, is described in U.S. Pat. No. 5,571,654.
• a toner consisting of resin, pigment and a three-way mixture as charge additive, in which the side chain of an aromatic carboxyl compound represents an alkoxy group, is described in U.S. Pat. No. 5,484,678.
• U.S. Pat. No. 5,346,793 describes a negatively charged toner consisting of resin particles, pigment particles and a charge enhancing additive obtainable from the reaction of an inorganic aluminum salt solution and an alkoxy-substituted benzoic acid.
• metal carboxylates and metal sulfonates defined below have good charge control properties, especially for negative charges and high thermal stability, the charge control property being lost neither by combination with carbon black nor by a combination with other colorants. Furthermore, the compounds are readily compatible with the customary toner, powder coating and electret binders and are easy to disperse.
• the present invention provides for the use of metal carboxylates and metal sulfonates as charge control agents in electrophotographic toners and developers, as charge improvers in powder coating materials, electret materials and in electrostatic separation processes, the metal carboxylates and metal sulfonates being prepared by reacting an acid A 1 and an acid A 2 in an aqueous alkaline medium, or by reacting an alkali metal salt of the acid A 1 and of the acid A 2 , with a water-soluble metal salt, wherein A 1 is
• R 1 is a linear or branched alkyl radical with 1 to 18 carbon atoms
• R 2 and R 3 are identical or different and are hydrogen, C 1 -C 8 -alkyl, (C 1 -C, 8 )-hydroxyalkylene, C 6 -C 10 -aryl, heteroaryl, e.g. pyridyl, imidazolyl, pyrazolyl, quinolinyl, isoquinolinyl, benzimidazolyl or indolyl, it being possible for aryl and heteroaryl to be substituted by from 1 to 3 of the radicals carboxyl, hydroxyl, C 1 -C 4 -alkoxy, C 1 -C 4 -alkyl, C 1 -C 4 -acyl, halogen, hydroxy-(C 1 -C 4 )-alkyl and amino, or are nitro, cyano, fluoro, chloro, bromo or C 1 -C 4 -acyl;
• R 4 , R 5 and R 6 are identical or different and are hydrogen, C 1 -C 8 -alkyl, (C 1 -C 8 )-hydroxyalkylene, C 6 -C 10 -aryl, heteroaryl, e.g.
• aryl and heteroaryl to be substituted from 1 to 3 of the radicals carboxyl, hydroxyl, C,-C 4 -alkoxy, C,-C 4 -alkyl, halogen, hydroxy-(C 1 -C 4 )-alkyl and amino, or are nitro, cyano, fluoro, chloro, bromo or C 1 -C 4 -acyl;
• n 1, 2 or 3
• n 0, 1 or 2;
• a polyanion-forming compound from the group consisting of poly(styrenesulfonic acid), poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(anetholesulfonic acid), poly(itaconic acid), polylvinyl sulfate), poly(vinylsulfonic acid), poly(acrylic acid-co-maleic acid), poly(styrenesulfonic acid-co-maleic acid), poly(ethylene-co-acrylic acid), hectorite, bentonite, algic acid, pectic acid, kappa-, lambda-, and iota-carrageenans, xanthan, gum arabic, dextran sulfate, carboxymethyidextran, carboxymethylcellulose, cellulose sulfate, starch sulfate, lignosulfonates, gum karaya; polygalacturonic acid, polyglucuronic acid, polyguluronic acid, poly
• n 5 to 5 ⁇ 10 5 ; and R 1 , X, A and Y are each identical or different and defined as follows:
• R 1 H or CH 3 ;
• A branched or linear (C 1 -C 18 )-alkylenes or arylenes, e.g. phenylene or naphthylene;
• copolymers consisting of monomers of the abovementioned compounds and one or more of the following monomers in varying composition: acrylic acid, methacrylic acid, acrylic acid alkyl-(C 1 -C 15 )-ester, methacrylic acid alkyl(C 1 -C 18 ) ester, glycidyl methacrylate, acrylamide, acrylonitrile, methacrylonitrile, ethylene, styrene, ⁇ -methylstyrene, styrenesulfonic acid, butadiene, butene, isoprene, vinyl chloride, propylene, maleic anhydride, maleic acid, maleic acid monoalkyl(C 1 -C 18 ) or dialkyl-(C 1 -C 18 ) ester, alkyl-(C 1 -C 18 ) vinyl ether, vinyl alcohol, vinyl acetate, vinylbutyral, vinylimidazole, N-vinyl-2-caprolactam, N-
• a 2 is an acid of formulae (I) to (VIII);
• the preparation of the metal carboxylates and metal sulfonates in an aqueous alkaline medium is judiciously performed at a temperature between 0 and 1 00° C, preferably between 10 and 90° C., and, in particular, between 15 and 85° C., under superatmospheric pressure if desired.
• the water-soluble metal salt, the acid A 1 and the acid A 2 are judiciously each employed in approximately equimolar amounts; in the case of the acids, there may be deviations of in each case up to 90 mol %.
• the water-soluble metal salt can, however, also be added in an excess: for example, in a from 1.1 to 6 times molar excess per carboxylate or sulfonate radical.
• M 2 is the divalent metal
• a 10 is the acid radical of the acid A 1 and
• a 20 is the acid radical of the acid A 2 , or else, exclusively or partly, a mixture of the compounds of the formulae A 10 —M 2 —A 10 and A 20 —M 2 —A 20 is formed.
• the acid A 1 and the acid A 2 can be employed in the same proportions as described above for divalent metals.
• the third ligand of the trivalent metal is a hydroxyl group.
• acids A 1 and A 2 employed can be identical or different, and it is possible for compounds of the formula (2)
• a 10 acid radical of the acid A 1 ,
• a 20 acid radical of the acid A 2 and
• M 3 trivalent metal
• acids A 1 and A 2 employed are different, i is possible for compounds of the formula (2) having correspondingly different acid radicals A 10 and A 20 to be formed. However, it is also possible that, partly or exclusively, a mixture of the compounds (A 10 ) 2 M 3 OH and (A 20 ) 2 M 3 OH is formed.
• the acids A 1 and A 2 and the metal salt in a molar ratio of about 2:1:1 or 1:2:1, in which case there may be deviations of in each case up to 90 mol % between the acids.
• the third ligand of the trivalent metal in this case it is also possible for the third ligand of the trivalent metal to be an acid radical of the acid A 1 or A 2 .
• the water-soluble metal salt can be employed, for example, in a from 1.1 to 6 times molar excess per carboxylate or sulfonate group.
• a 30 acid radical A 10 or A 20 .
• acid radicals in the said mixture can be replaced by OH.
• Preferred metal cations M 2+ are Zn 2+ , Fe 2+ , Co2+, Mn 2+ , N?2+, Cu 24 , Mg 2+ , Ca 2+ ,Sr 2+ and Ba 2+ .
• Preferred metal cations M 3+ are Al 3+ , Fe 3+ , Mn 3+ and Co 3+ .
• Water-soluble metal salts employed are preferably salts of said cations with anions from the group consisting of fluoride, chloride, bromide, sulfate, hydrogen sulfate, carbonate, hydrogencarbonate, nitrate and hydroxide with which sufficient water-solubility in alkaline solution is provided.
• the pH of the alkaline solution is adjusted to from 7.5 to 13 using a metal hydroxide M′OH, M 2 (OH) 2 or M 3 (OH) 3 , preferably NaOH. It is also possible to employ the above-described metal cations directly in the form of their hydroxides.
• a judicious procedure is to slurry the acids A 1 and A 2 in water, adjust said pH using NaOH, and meter in a solution of water-soluble metal salt.
• the desired product usually precipitates and is isolated and dried.
• Preferred acids A 1 in the context of the present invention are:
• polyester consisting of the reaction product of the individual components i), ii) and iii) and also, if desired, iv) and, if desired, v), where
• i) is a dicarboxylic acid or a reactive derivative of a dicarboxylic acid which is free from sulfo groups
• ii) is a difunctional aromatic, aliphatic or cycloaliphatic sulfo compound whose functional groups are hydroxyl or carboxyl, or hydroxyl and carboxyl,
• iii) is an aliphatic, cycloaliphatic or aromatic diol, a polyether diol or a polycarbonate diol,
• iv) is a polyfunctional compound (functionality >2), whose functional groups are hydroxyl or carboxyl, or hydroxyl and carboxyl, and
• v) is a monocarboxylic acid or a sulfo-containing monoalcohol.
• Particularly preferred acids A 1 from groups a) to d) are:
• Preferred acids A 2 in the context of the present invention are:
• metal carboxylates and metal sulfonates for the purposes of the present invention are compounds of the formula (1) in which
• a 10 is 4-tert-butylbenzoate, poly(ethylenesulfonate), poly(styrenesulfonate), poly(methacrylate), diphenyl disulfide 2,2′-dicarboxylate,
• a 20 is 4-tert-butylbenzoate, diphenyl disulfide 2,2′-dicarboxylate, salicylate and M 2+ is Zn 2+ ,
• a 10 and A 20 are as defined above,
• a 30 is OH, poly(methacrylate), poly(styrenesulfonate), poly(ethylenesulfonate), salicylate or diphenyl disulfide 2,2′-dicarboxylate, and
• M 3+ is Al 3+ .
• the carboxyl- and/or sulfo-containing polyesters of group d) are described, for example, in EP-A 2 -0 644 463, especially in the Preparation Examples therein under 1.1.
• the metal carboxylates and metal sulfonates used in accordance with the invention can be matched precisely to the particular resin/toner system.
• a further factor is that the compounds employed in accordance with the invention are free-flowing and possess high and particularly constant charge control properties, good thermal stabilities and good dispersibilities.
• a further technical advantage of these compounds is that they are inert toward the various binder systems and can therefore be employed widely, it being particularly significant that they are not dissolved in the polymer matrix but rather are present as small, very finely divided solid structures.
• Dispersion means the distribution of one substance within another, i.e. in the context of the invention the distribution of a charge control agent in the toner binder, powder coating binder or electret material.
• crystalline substances in their coarsest form are present as agglomerates. To achieve homogeneous distribution within the binder, these agglomerates must be disrupted by the dispersing operation into smaller aggregates, or ideally, into primary particles.
• the particles of charge control agent present in the binder following dispersion should be smaller than 1 ⁇ m, preferably smaller than 0.5 ⁇ m, with a narrow particle size distribution being of advantage.
• the particle size defined by the d 50 value
• coarse particles ⁇ 1 mm
• the particle size and form is established and modified either by the synthesis and/or by aftertreatment.
• the required property is frequently possible only through control of the treatment, such as milling and/or drying.
• Various milling techniques are suitable for this purpose. Examples of advantageous technologies are airjet mills, cutting mills, hammer mills, bead mills and impact mills.
• the binder systems mentioned in connection with the present invention are, typically, hydrophobic materials.
• High levels of water in the charge control agent can either oppose wetting or else promote dispersion (flushing).
• the practicable moisture content is therefore specific to the particular material.
• the compounds employed in accordance with the invention feature the following chemical/physical properties:
• the water content determined by the Karl-Fischer method, is between 0.01% and 30%, preferably between 0.05 and 25% and, with particular preference, between 0.05 and 20%, it being possible for the water to be in adsorbed and/or bonded form, and for its proportion to be adjusted by the action of heat at up to 200° C. and reduced pressure down to 10 ⁇ 8 torr or by addition of water.
• the particle size determined by means of evaluation by light microscope or by laser light scattering, and defined by the devalue, is between 0.01 ⁇ m and 1000 ⁇ m, preferably between 0.1 and 500 ⁇ m, and with very particular preference between 0.2 and 400 ⁇ m.
• milling results in a narrow particle size fraction. Preference is given to a range ⁇ (d 95 -d 50 ) of less than 500 ⁇ m, in particular less than 200 ⁇ m.
• the metal carboxylates and metal sulfonates employed in accordance with the invention can also be combined with further positive or negative charge control agents in order to obtain good performance chargeabilities, the overall concentration of these charge control agents being between 0.01 and 50% by weight, preferably between 0.1 and 5% by weight, based on the overall weight of the electrophotographic toner, developer, powder or powder coating material.
• Suitable further charge control agents are: triphenylmethane; ammonium and immonium compounds, iminiumcompounds, fluorinated ammonium and fluorinated immonium compounds; biscationic acid amides; polymeric ammonium compounds; diallylammonium compounds; aryl sulfide derivatives, phenol derivatives; phosphonium compounds and fluorinated phosphonium compounds; calix(n)arenes, cyclically linked oligosaccharides (cyclodextrins) and their derivatives, especially boric ester derivatives, interpolyelectrolyte complexes (IPECs); polyester salts; benzimidazolones; azines, thiazines or oxazines, which are listed in the Colour Index as Pigments, Solvent Dyes, Basic Dyes or Acid Dyes, or metal azo complex dyes.
• the metal carboxylates and metal sulfonates used in accordance with the invention and, if desired, further charge control agents are incorporated individually or in combination with one another in a concentration of from 0.01 to 50% by weight, preferably from 0.5 to 20% by weight, particularly preferably from 0.1 to 5.0% by weight, based on the overall mixture, into the binder of the respective toner, developer, coating material, powder coating material, electret material or of the polymer which is to be electrostatically separated, said incorporation being homogeneous and taking place, for example, by means of extrusion or kneading, beadmilling or using an Ultra-Turrax (high-speed stirrer).
• Ultra-Turrax high-speed stirrer
• the compounds employed in accordance with the invention can be added as dried and milled powders, dispersions or solutions, press cakes, masterbatches, preparations, made-up pastes, as compounds applied from aqueous or non aqueous solution to appropriate carriers such as silica gel, TiO 2 , Al 2 O 3 or carbon black, for example, or mixed with such carriers, or added in some other form.
• appropriate carriers such as silica gel, TiO 2 , Al 2 O 3 or carbon black, for example, or mixed with such carriers, or added in some other form.
• the compounds used in accordance with the invention can also in principle be added even during the preparation of the respective binders, i.e., in the course of their addition polymerization, polyaddition or polycondensation.
• the present invention additionally provides an electrophotographic toner comprising a customary binder, for example a styrene, styrene-acrylate, styrene-butadiene, acrylate, acrylic, polyester or epoxy resin or a combination of the last two, and from 0.01 to 50% by weight, preferably from 0.5 to 20% by weight, and, with particular preference, from 0.1 to 5% by weight, based in each case on the overall weight of the electrophotographic toner, and at least one metal carboxylate or metal sulfonate, alone or in combination with one or more of the above-described additional charge control agents.
• a customary binder for example a styrene, styrene-acrylate, styrene-butadiene, acrylate, acrylic, polyester or epoxy resin or a combination of the last two, and from 0.01 to 50% by weight, preferably from 0.5 to 20% by weight, and, with particular preference, from 0.1 to 5% by weight,
• the electrophotographic toner can additionally comprise from 1 to 10% by weight, preferably from 2 to 8% by weight, of a colorant, for example, a dye, an organic or inorganic color pigment or a black pigment, such as carbon black, for example.
• a colorant for example, a dye, an organic or inorganic color pigment or a black pigment, such as carbon black, for example.
• the present invention also provides a powder coating material comprising a customary binder, such as a urethane, acrylic, polyester or epoxy resin or a combination thereof, and from 0.01 to 50% by weight, preferably from 0.5 to 20% by weight and, with particular preference, from 0.1 to 5% by weight, based in each case on the overall weight of the powder coating material, of at least one metal carboxylate or metal sulfonate, alone or in combination with one or more of the above-described additional charge control agents.
• the powder coating material can additionally contain from 1 to 10% by weight, preferably from 2 to 8% by weight, of a colorant, for example a dye, an organic or inorganic color pigment or a black pigment, such as carbon black, for example.
• Crystallinity very high crystallinity (>95%, by X-ray); numerous sharp reflection peaks between 2theta 5° and 35° (main peaks: 6.6°, 7.00, 15.2° and 21.40 and 21.70)
• Crystalinity 70% crystallinity (X-ray analysis); numerous sharp reflection peaks between 2theta 5° and 350 (main peaks: 7.60, 9.70, 14.90, 15.50 and also 26.0° and 30.00)
• Resin 1 60:40 styrene-methacrylate copolymer
• Resin 2 Bisphenol-based polyester (OAlmacryl resin)
• Carrier 2 silicone-coated ferrite particles of size 50 to 100 ⁇ m (bulk density 2.75 glcm 3 ) (FBM 96-1 1A; from Powder Techn.)
• a toner binder 60:40 styrene-metahcrylate copolymer, resin 1, ®Dialec S 309
• the composition is then ground on a laboratory universal mill and subsequently classified in a centrifugal classifier.
• the desired particle fraction (4 to 25 ⁇ m) is activated with a carrier (Carrier 1).
• each metal carboxylate or metal sulfonate is incorporated into the respective resin using a kneader, as described in Use Example 1.
• Measurement is carried out on a customary q/m measurement stand. By using a sieve having a mesh size of 50 ⁇ m it is ensured that no carrier is entrained when the toner is blown out. Measurements are made at 50% relative atmospheric humidity. The q/m values [pC/g] are measured as a function of the activation period. The q/m values of Use Examples 2 to 33 are given in Table 2. The amounts of respective metal carboxylate or metal sulfonate are in each case 1% by weight. q/m values for Use Example 1:
• the respective charge of the sprayed powder was subsequently measured with a device from Intec for measuring the triboelectric charge of powders.
• the measuring antenna of the device was held directly in the cloud of powder emerging from the spraying device.
• the current strength resulting from the electrostatic charge of powder coating material or powder was indicated in ⁇ A.
• the deposition rate was subsequently determined, in %, by differential weighing of sprayed and deposited powder coating material.
• the compound from Use Example 1 is treated as in Use Example 1 except that the sample of the subsequent qim measurement is stored not at the usual relative atmospheric humidity (between 35 and 65%) but instead at a relative atmospheric humidity of 10% (25° C.) for 24 h, this humidity being established in a climatically controlled cabinet (from Espec).

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• 1998
  • 1998-08-19 DE DE19837522A patent/DE19837522A1/de not_active Withdrawn
• 1999
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